I've heard that if you put mercury in a bullet, the bullet will explode on impact. But this doesn''t make sense to me.

Leaving behind the "mercury forms alloy's at room temp easily", it seems that just putting mercury in a bullet won't make it explode because:

When it hits the target wouldn't the mercury squirt out the back of the bullet?

Or when it hits, the mercury would squirt out the sides, because it is a liquid, and so would not hold it's shape enough to penetrate a body to a great degree

So is the mercury bullet exploding thing an Urban legend (I googled mercury bullet site:www.straightdope.com and got nothing, and I'm looking through snopes (search: mercury bullet = no matches), but haven't found anything yet, so any help on the mercury bullet would be nice)

From what I remember (no time to look for a cite) a cavity in the bullet contains some mercury, some air. On impact the mercury hits the front of the cavity with enough force to vaporize, making it explode.

A buddy of mine in high school tried this, and was sorely disappointed with the results. He was using a .44 with hollow points, IIRC. According to him, the mercury never made it to the target, it being vaporized when the bullet was fired.

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From what I've heard, a bullet filled partially with liquid mercury produces violent shockwaves on impact.

1) The mercury-filled bullet would pack a bit more wallop because mercury has a specific gravity of 13.55 compared to 11.3 for lead.

2) Mercury, being a liquid, would splatter on impact as opposed to the lead which would remain solid. This is vaguely analagous to a hollow-point bullet but now instead you have a "liquid-point" bullet.

Mercury tipped rounds have a channel drilled in them that is filled with mercury, then capped. When the bullet hits a target, the round literally explodes as the mercury is compressed and ruptures the lead.

Wasn't it mercury-filled bullets in the book version of The Day of the Jackal?*

IIRC, you drill a relatively deep, narrow hole in the lead, partially fill the whole with mercury, and then tap some more lead on top to seal whole. When the bullet is fired, the mercury builds up in the rear of the bullet, at impact the mercury is flung forward and pops off the lead cap, and little driblets of both go scattering through the target tissue.

The mercury was never intended to explode, in a chemical sense.

*IANAL chemist, weapons expert, just someone who's read hundreds of spy novels and have trouble distinguishing fact from fiction, and sometimes which book they came from.

In order to inflict maximum damage to your target, your bullets need a balance between penetration and expansion. Too much expansion results to minimal penetration, ie a surface wound. Too little expansion and the bullet will go right through flesh, doing little damage.
I don't see how mercury bullets do more damage.

Wasn't it mercury-filled bullets in the book version of The Day of the Jackal?

I was going to mention that very book.

In a small hollow inside the bullet the mercury rest and is held at the back of the bullet by the acceleration of firing, then carries forward when the deceleration of impact occurs and expands out the front of the bullet.

Frederick Forsyth describes the manufacture of mercury bullets in the book Day of the Jackal at some length. I'm ot an arms specoialist, but it seemed pretty convincing. He was a journalist, so you'd think he got his facs straight. On the other hand, I am an optics guy, and I know thathe really messed up the explanation of image-intensifier tubes in another book. So maybe he just has a convincing manner. The book and the movie imply that you can make these with glycerine, as well.

The bullet used in DOTJ has a hole drilled in it, a drop of mercury placed in it, and it's then re-sealed with lead and the shape re-constructed. The explanation Forsyth gives is that, upo impact, he mercury is thrown forward and rips the tip of the bullet apart, and the shrapnel continues to tear apart whatever body part it hit.

My question is: Why doesn't the same thing happen when the bullet is accelerated when the gun is fired? Wouldn't the same inertia tend to tear the [i]back[/i[] of the bullet apart? (Even if the gases propel mercury and all forward, and even if the casing helps hold it together, it seems to me the bullet would be fragmented , the mercury gone from the compartment, so that when the bullet finally it degaulle's head (or whatever target) it wouldn't be able to explode.

A later movie (not by Forsyth), The Exterminator, showed the killer manufacturing such bullets in what looked even to my untrained eyes like a very dangerous and stupid procedure, but evidently trying to do it as described in Forsyth's book. I'd be willing to bet the screenwriter read DOTJ.

No fulminate is involved in any of the above. The "explosion" is a purely mechanical effect.

In he case of Hunckley's assault on Reagan, it's my understanding that he used azide bullets, which are explosive due to a chemical effect (although not the same as fulminate).

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I don't know what the length of the shell was, but I imagine you could driill the hole so the lead at the rear is a doozen or more times thicker than the nose cap. If the lead slug is half an inch long, you drill the hole a quarter inch deep, and the noe cap is a tapped-on thiryseconth of an inch.

I'm only using these numbers as examples, I have no idea what the true proportions should be, assuming the idea works at all. But it would explain conceptually why the rear of the bullet could absorb the impact of mercury non-destructively.

Frederick Forsyth describes the manufacture of mercury bullets in the book Day of the Jackal at some length. I'm not an arms specialist, but it seemed pretty convincing. He was a journalist, so you'd think he got his facts straight. On the other hand, I am an optics guy, and I know that he really messed up the explanation of image-intensifier tubes in another book. So maybe he just has a convincing manner.

HAAHAAAAHAAA!!! Journalist used in same sentence as "get facts straight" when dealing with a technical topic. That's mighty funny, especially given your doubt in the next sentence. I vote for convincing manner. That's why he gets paid to write!

Hence convieniently making the whole argument about mercury filled bullets moot, unless someone has a cite about them REALLY being used.

I read DotJ as a child and I was highly skeptical because the difference in mass due to the relatively modest difference in density would be in the milligrams, not grams, for the method of construction described, this puts a real limit on the force. As a young adult, I was into "reloading" which includes casting bullets, and that confirmed my suspicion even a molten plug would probably come out relatively cleanly, rather than passing enough force to the surrounding slug to shatter it. A nonmolten plug definitely would

If you made a more substantial cavity in the bullet, you'd weaken the walls, which might assist the deformation on impact and help the plug adhere to the walls. This thin-wall might be supported by the barrel during firing, but not during impact, but you'd have to work a delicate balance. Is that possible for a professional assassin who is willing to do substantial experimentation in advance with a specific bullet and load? Maybe, but I think it would still be risky and iffy --and probably still wouldn't yield sufficient force for the desired result

I hope some metallurgist can comment on the miscibility or amalgamation of liquid lead and mercury, which was something I never got aroung to looking up. If mercury amalgams with lead as it doeas with many other metals, the difference in density would be reduced. I don't know what the properties of the amalgam would be. It might fragment easily.

Still, as others have noted, the fact that this is not used by our professional sniper forces, whose ammunition is all handmade, and who grasp at any advantage, strongly militates against it being effective.

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